Composites and composite membranes

ABSTRACT

The invention relates to a composite or a composite membrane consisting of an ionomer and of an inorganic optionally functionalized phyllosilicate. The isomer can be: (a) a cation exchange polymer; (b) an anion exchange polymer; (c) a polymer containing both anion exchanger groupings as well as cation exchanger groupings on the polymer chain; or (d) a blend consisting of (a) and (b), whereby the mixture ratio can range from 100% (a) to 100% (b). The blend can be ionically and even covalently cross-linked. The inorganic constituents can be selected from the group consisting of phyllosilicates or tectosilicates.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation of the U.S. National Phase ofInternational Application No. PCT/EP00/03910, filed May 2, 2000, nowpublished as WO 00/74827, which claims priority to German PatentApplication No. DE 199 19 881.0, filed Apr. 30, 1999, the entiredisclosure of each of which is hereby incorporated by express referencehereto.

FIELD OF THE INVENTION

[0002] The present invention involves providing composites which possessa high ion conductivity (especially proton conductivity) andsimultaneously limited swelling ability and permit an operatingtemperature in electrochemical cells of above 100° C. The inventionrelates thus to an ion conducting composite containing an acid and/or anorganic base and a phyllosilicate, wherein the composition of theacid-base part is present in an amount from 1 to 99 weight % and thephyllosilicate is present in an amount from 99 to 1 weight %.

BACKGROUND OF THE INVENTION

[0003] Ionomer membranes are used in many processes, for example, inmembrane fuel cells, in electrodialysis, in diffusion dialysis, inelectrolysis (PEM electrolysis, chlorine alkali electrolysis), or inelectrochemical processes.

[0004] A disadvantage of the actual membranes is, however, that theirproton conductivity at temperatures above 100° C. in most casesdecreases rapidly due to drying up of membranes. Temperatures above 100°C. are, however, very interesting for fuel cell applications of ionomermembranes, because above 100° C. the temperature regulation of fuelcells is greatly simplified and the catalysis of the fuel cell reactionis substantially improved (excess voltage decreased, no CO-loading anymore, which poisons the catalyst).

[0005] Only a few examples of membranes which still exhibit good protonconductivity even above 100° C. are known from the literature, forexample poly(phenylene)s havingcarbonyl-1,4-phenylene-oxyphenyl-4-sulfonic acid side groups. Howeverthe proton conductivity of these membranes decreases rapidly above 130°C., and the reason for the good proton conductivity between 100° C. and130° C. is also not clear.

[0006] Proton conductivity is based on the Grotthus mechanism withprotons in acidic media and hydroxyl ions in alkaline media acting ascharge carriers. There exists a structure crosslinked via hydrogen bondsenabling the actual charge transport. That means the water contained inthe membrane plays an important part in the charge transport: withoutthis additional water, there is no mentionable charge transport acrossthe membrane in these commercially available membranes; they lose theirfunction. Other new developments, which use phosphate backbones insteadof a fluorohydrocarbon backbone, also need water as an additionalnetwork builder. (Alberti et al., SSPC9, Bled, Slowenia, 17.-21.8.1998,Extended Abstracts, p. 235). While the addition of small SiO₂ particlesto the above mentioned membranes (Antonucci et al., SSPC9, Bled,Slowenia, 17.-21.8.1998, Extended Abstracts, p. 187) leads to astabilization of proton conductivity up to 140° C., this only appliesunder operating conditions of a pressure of 4,5 bar. Without increasedoperating pressure, these membranes also lose their water network above100° C. and dry up. A substantial disadvantage of all the abovementioned membrane types is therefore that, even under best operatingconditions, they are usable at application temperatures of up to 100° C.

[0007] In the same manner as mentioned above, Denton et al. U.S. Pat.No. 6,042,958) prepared composites from ion conducting polymers andporous substrates. As silica containing components, they used glass,ceramics, or silica. In the examples described therein, the operatingtemperature was not increased above 80° C.

[0008] While in the direct methanol fuel cell (DMFC) sufficient water ispresent, methanol crossover through the membrane, however, results in asubstantial decrease of power.

[0009] If composites of sulfonated polyaryletheretherketone membranes(European Patent No. EP 0574791 B1) or sulfonated polyethersulfone andsilica are prepared, the membrane swells at an cation-exchange capacityof 1.5 meq/g to an extent that it is ultimately destroyed.

[0010] Phyllosilicates (clay minerals) have some interesting properties:

[0011] They can bind hydrate water up to 250° C.

[0012] In these materials, metal cations and metal oxides can beadditionally incorporated, inducing hereby an intrinsic protonconductivity according to the general scheme:

M^(n+)(H₂O)→(M—OH)^((n-1)−)+H⁺

[0013] [Zeolite, Clay and Heteropoly Acid in Organic Reactions, Y.Izumi, K. Urabe, M. Onaka; 1992; Weinheim, VCH-Verlag, p. 26].

[0014] Phyllosilicates having Lewis acid cavities may intercalate byacid-base interaction with the basic groups of basic polymers[Kunststoffhanokomposite, symposium: Von der Invention zur Innovation,Publication at the Symposium of the Fonds of the Chemical Industry, May6, 1998, in Cologne].

[0015] Due to these properties, some types of phyllosilicate/polymercomposites have been synthesized. Muhlhaupt et al made composites frommontmorillonite and polypropylene, montmorillonite and polyamide, andmontmorillonite and PERSPEX™. In these composites, for example, thePERSPEX becomes hardly flammable, due to the admixture withmontmorillonite, because the incorporated phyllosilicates are barriersto the pyrolysis gases formed on combustion.

DESCRIPTION OF THE FIGURE

[0016]FIG. 1 is a depiction of three (3) embodiments of the invention.

SUMMARY OF THE INVENTION

[0017] The advantage of the composites according to the invention, andthe membranes prepared therewith, is the incorporation of an organiccomponent, especially of protonated nitrogen bases, into the cavities ofthe phyllosilicates, which is a cross-linking component, when the baseis provided on a polymer backbone. Furthermore, the selectiveincorporation of cations or metal hydroxides with subsequent reaction tothe corresponding metal oxides permits varying the Lewis acid propertiesand size of the membrane cavities in a wide range. Moreover, thephyllosilicates can be functionalized to interact with ionomers in whichthey are embedded or to influence the surrounding medium according totheir functional group.

[0018] The invention relates to an ion conducting composite comprising:(A) a polymer; (B) an acid-base component comprising an acid and/or abase; and (C) a phyllosilicate and/or tectosilicate, wherein components(A) and (B) can be combined into a polymer comprising an acidic and/orbasic group. The sum of the amounts of the acid-base component and thepolymer are from 1 to 99 weight % and the amount of phyllosilicateand/or tectosilicate is from 99 to 1 weight %. The acid and/or a base ispresent in the cavities of the phyllosilicate and/or tectosilicate.

[0019] In one embodiment, an ionomer is used as the combination ofcomponents (A) and (B) and is selected from the group consisting of:

[0020] (a) a cation exchange polymer comprising a cation exchange group—SO3H, —COOH, and/or —PO₃H₂, wherein the polymer can be non-cross-linkedor covalently crosslinked and the polymer backbone can be a vinylpolymer, an aryl main chain polymer, polythiazole, polypyrazole,polypyrrole, polyaniline, polythiophene or any blend of these;

[0021] (b) an anion exchange polymer comprising an anion exchange group—NR₃ ⁺, PyrH⁺, ImR⁺, PyrazR⁺, TriR⁺, and/or other organic basic aromaticand/or non-aromatic groups, wherein R is a hydrogen, alkyl, or arylgroup, wherein the polymer is non-cross-linked or covalentlycrosslinked, and wherein the polymer comprises a vinyl polymer, an arylmain chain polymer, polythiazole, polypyrazole, polypyrrole,polyaniline, polythiophene, or a blend thereof;

[0022] (c) a polymer containing on the polymer chain both anion exchangegroups from (b) and cation exchange groups from (a), wherein the polymercomprises a vinyl polymer, an aryl main chain polymer, polythiazole,polypyrazole, polypyrrole, polyaniline, polythiophene, or a blendthereof; or

[0023] (d) a blend of (a) and (b), wherein the mixing ratio can rangefrom 100% of (a) to 100% of (b), wherein the blend is covalently andionically cross-linked, and wherein the polymer comprises a vinylpolymer, an aryl main chain polymer, polythiazole, polypyrazole,polypyrrole, polyaniline, polythiophene, or a blend thereof.

[0024] Preferably, the ionomer is an ionomer blend (d), and thephyllosilicate is montmorillonite or clinoptilolite.

[0025] In another embodiment, a precursor of the ionomer is used as thecombination of components (A) and (B) and is selected from the groupconsisting of:

[0026] (a) the precursor of: a cation exchange polymer (a1) comprisingCOHal, CONR₂, or COOR groups; a cation exchange polymer (a2) comprisingSO₂Hal, SO₂NR₂, or SO₂OR groups; or a cation exchange polymer (a3)comprising PO₃Hal₂, PO₃(NR₂)₂, or PO₃(OR)₂ groups, wherein R is ahydrogen, alkyl, or aryl group, and wherein Hal is a fluorine, chlorine,bromine, or iodine atom; or

[0027] (b) the precursor of an anion exchange polymer comprising —NR₂,pyridyl, imidazolyl, pyrazolyl, triazolyl, and/or other organic basicaromatic and/or non-aromatic groups, wherein R is a hydrogen, alkyl, oraryl group, and wherein Hal is a fluorine, chlorine, bromine, or iodineatom.

[0028] Advantageously, the phyllosilicate is a bentonite. Morepreferably, the bentonite is montmorillonite. Alternatively, thephyllosilicate may be a pillared phyllosilicate, and/or thetectosilicate may be a zeolite, such as clinoptilolite.

[0029] In one embodiment, the basic component contains imidazole,vinylimidazole, pyrrazole, oxazole, carbazole, indole, isoindole,dihydrooxazole, isooxazole, thiazole, benzothiazole, isothiazole,benzoimidazole, imidazolidine, indazole, 4,5-dihydropyrazole,1,2,3-oxadiazole, furazane, 1,2,3-thiadiazole, 1,2,4-thiadiazole,1,2,3-benzotriazole, 1,2,4-triazole, tetrazole, pyrrole, aniline,pyrrolidine, or pyrrazole groups.

[0030] In one embodiment, the polymer component (A) comprises an acidpolymer, and wherein the backbone of the polymer comprises one or moreof the following repeat units: R_(aromatic) R_(bridge)

[0031] If the polymer component (A) is a basic polymer, the backbone ofthe polymer may comprise one or more of the repeat units above or one ormore of the following repeat units:

[0032] Components (A) and (B) may be combined into 1) a polymercomprising an acidic group and 2) a polymer comprising a basic group.

[0033] The composite is useful as a component in a fuel cell whichoperates at temperatures from −40° C. to 200° C., or a reverse osmosisor (electro)membrane separator which separates two or more gases orliquids with a membrane comprising the composite. The composite is alsouseful as a component in a catalytic membrane or a membrane reactor.Advantageously, the composite exhibits thermal resistance up to 400° C.

[0034] The invention also contemplates a process for the preparation ofthe composite, wherein the polymer component, the acid-base component,and the phyllosilicate and/or tectosilicate component are brought intocontact, optionally with a solvent, at a temperature from −40° C. to300° C.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] (a) The acid may be a cation exchange polymer (having cationexchange groups —SO₃H, —COOH, —PO₃H₂, wherein the polymer can bemodified with only one of the described cation exchange groups or with ablend of the described cation exchange groups); wherein the polymer canbe not cross-linked or covalently cross-linked. The ion exchangecapacity in general is comprised between 0.1 and 12 meq/g, morepreferably between 0.3 and 8 meq/g, most preferably between 0.5 and 2meq/g. Particularly preferred as backbone are thermoplastics.

[0036] (b) The acid can also be an organic or inorganic low molecularweight acid. In the inorganic acid case, sulfuric and phosphoric acidare particularly preferred. In the organic acid case, all low molecularweight acids that are sulfonic or carboxylic acids are taken intoconsideration, especially all amino sulfonic acids and theaminosulfochlorides as their precursors.

[0037] (c) The base may be an anion-exchange polymer (having anionexchange groups —NR₃ ⁺(R═H, alkyl, aryl), pyridinium (PyrR⁺),imidazolium ImR⁺), pyrazolium (PyrazR⁺), triazolium (TriR⁺), and otherorganic basic aromatic and/or non-aromatic groups (R═H, alkyl, aryl),wherein the polymer can be modified with only one of the described anionexchange groups or with a blend of the described anion exchange groups);and wherein the polymer can be non-cross-linked or covalentlycross-linked. The anion exchange capacity herein is preferably between 1and 15 meq/g, more preferably between 3 and 12 meq/g, most preferablybetween 6 and 10 meq/g. Preferred as backbone are again allthermoplastics, particularly polysulfone, polyetheretherketone,polybenzimidazole, and polyvinylpyridine.

[0038] (d) The base can be an organic or inorganic low molecular weightbase. As an organic low molecular weight base, all guanidine derivativesare particularly preferred.

[0039] (e) The functional group of the acid and the base may be in thesame molecule. This molecule can be low or high molecular weight. If itis a polymer, then on the polymer chain there are anion exchange groupsfrom (c) as well as cation exchange groups from (a).

[0040] (f) The above-mentioned acids and bases of (a) to (e) may beblended in the composite. Any mixing ratio can be chosen. The blend canbe further covalently cross-linked, in addition to the ioniccross-linking.

[0041] (g) If both the acid and the base are low molecular weight, thereis in addition an unmodified polymer contained in the composite.

[0042] (h) The inorganic active filler is a phyllosilicate based onmontmorillonite, smectite, illite, sepiolite, palygorskite, muscovite,allevardite, amesite, hectorite, talc, fluorhectorite, saponite,beidelite, nontronite, stevensite, bentonite, mica, vermiculite,fluorvermiculite, halloysite, fluor containing synthetical talc types,or blends of two or more of the above-mentioned phyllosilicates. Thephyllosilicate can be delaminated or pillared. Particularly preferred ismontmorillonite.

[0043] The weight ratio of the phyllosilicate is preferably from 1 to80%, more preferably from 2 to 30% by weight, most preferably from 5 to20%.

[0044] The term “a phyllosilicate” in general means a silicate, in whichthe SiO₄ tetraeders are connected in two-dimensional infinite networks.(The empirical formula for the anion is (Si₂O₅ ²⁻)_(n)). The singlelayers are linked to one another by the cations positioned between them,which are usually Na, K, Mg, Al, or/and Ca, in the naturally occurringphyllosilicates.

[0045] By the term “a delaminated functionalized phyllosilicate,” weunderstand phyllosilicates in which the layer distances are at firstincreased by reaction with so-called functionalisation agents. The layerthickness of such silicates before delamination is preferably 5 to 100angstroms, more preferably 5 to 50, and most preferably 8 to 20angstroms. To increase the layer distances (hydrophobization), thephyllosilicates are reacted (before production of the compositesaccording to the invention) with so-called functionalizinghydrophobization agents, which are often also called onium ions or oniumsalts.

[0046] The cations of the phyllosilicates are replaced by organicfunctionalizing hydrophobization agents, whereby the desired layerdistances which depend on the kind of the respective functionalizingmolecule or polymer which is to be incorporated into the phyllosilicatecan be adjusted by the kind of the organic residue.

[0047] The exchange of the metal ions can be complete or partial.Preferred is the complete exchange of metal ions. The quantity ofexchangeable metal ions is usually expressed as milli equivalent (meq)per 1 g of phyllosilicate and is referred to as ion exchange capacity.Preferred are phyllosilicates having a cation exchange capacity of atleast 0.5, preferably 0.8 to 1.3 meg/g.

[0048] Suitable organic functionalizing hydrophobization agents arederived from oxonium, ammonium, phosphonium, and sulfonium ions, whichmay carry one or more organic residues.

[0049] As suitable functionalizing hydrophobization agents, those ofgeneral formula I and/or II are mentioned:

[0050] where the substituents have the following meaning:

[0051] R₁, R₂, R₃, and R₄ are independently from each other: hydrogen, astraight chain, branched, saturated or unsaturated hydrocarbon radicalwith 1 to 40, preferably 1 to 20, C atoms, optionally carrying at leastone functional group, or 2 of the radicals are linked with each other,preferably to a heterocyclic residue having 5 to 10 C atoms, morepreferably having one or more N atoms,

[0052] X represents phosphorous or nitrogen,

[0053] Y represents oxygen or sulfur,

[0054] n is an integer from 1 to 5, preferably 1 to 3, and

[0055] Z is an anion.

[0056] Suitable functional groups are hydroxyl, nitro, or sulfo groups,whereas carboxyl or sulfonic acid groups are especially preferred. Inthe same way, sulfochloride and carboxylic acid chloride groups areespecially preferred.

[0057] Suitable anions, Z, are derived from proton delivering acids, inparticular mineral acids, wherein halogens, such as chlorine, bromine,fluorine, iodine, sulfate, sulfonate, phosphate, phosphonate, phosphite,and carboxylate, especially acetate, are preferred. The phyllosilicatesused as starting materials are generally reacted as a suspension. Thepreferred suspending agent is water, optionally mixed with alcohols,especially lower alcohols having 1 to 3 carbon atoms. If thefunctionalizing hydrophobization agent is not water-soluble, then asolvent is preferred in which said agent is soluble. In such cases, thisis especially an aprotic solvent. Further examples for suspending agentsare ketones and hydrocarbons. Usually, a suspending agent miscible withwater is preferred. On addition of the hydrophobizing agent to thephyllosilicate, ion exchange occurs, whereby the phyllosilicate usuallyprecipitates from the solution. The metal salt resulting as a by-productof the ion exchange is preferably water-soluble, so that thehydrophobized phyllosilicate can be separated as a crystalline solid,for example, by filtration.

[0058] The ion exchange is mostly independent from the reactiontemperature. The temperature is preferably above the crystallizationpoint of the medium and below the boiling point thereof. For aqueoussystems, the temperature is between 0 and 100° C., preferably between 40and 80° C.

[0059] For a cation and anion exchange polymer, alkylammonium ions arepreferred, in particular if, as a functional group, additionally acarboxylic acid chloride or sulfonic acid chloride is present in thesame molecule. The alkylammonium ions can be obtained via usualmethylation reagents, such as methyl iodide. Suitable ammonium ions areomega-aminocarboxylic acids; especially preferred areomega-aminosulfonic acids and omegaalkylaminosulfonic acids.Omega-aminosulfonic acids and omega-alkylaminosulfonic acids can beobtained with usual mineral acids, for example, hydrochloric acid,sulfuric acid, or phosphoric acid, or by methylation reagents, such asmethyl iodide.

[0060] Additional preferred ammonium ions are pyridine andlaurylammonium ions. After hydrophobizing, the layer distance of thephyllosilicates is in general between 10 and 50 angstroms, preferablybetween 13 and 40 angstroms.

[0061] The hydrophobized and functionalized phyllosilicate is freed ofwater by drying. In general, a thus treated phyllosilicate stillcontains a residual water content of 0-5 weight % of water.Subsequently, the hydrophobized phyllosilicate can be mixed in form of asuspension in a suspending agent, which is free as much as possible fromwater with the mentioned polymers and can be further processed.According to the invention, the polymers, especially preferably thethermoplastic functionalized polymers (ionomers), are added to thesuspension of the hydrophobized phyllosilicates. This can be done usingalready dissolved polymers, or the polymers are dissolved in thesuspension itself. Preferably, the ratio of the phyllosilicates isbetween 1 and 70 weight %, more preferably between 2 and 40 weight %,and most preferably between 5 and 15 weight %.

[0062] Process for producing the composite

[0063] The present invention concerns, furthermore, a process forproducing composite membranes. In the following, process examples toproduce proton conducting composites having high proton conductivity aredescribed.

[0064] 1) An aminoarylsulfochloride is dissolved in tetrahydrofuran.Then, a corresponding quantity of montmorillonite K10 is added. Themontmorillonite is proton exchanged and dried. Then, stirring forseveral hours follows. The time of stirring depends on the molecularsize of the aminoarylsulfochloride and the ratio of the amino group tothe cation exchange capacity of the montmorillonite. During the stirringprocess, the amino group intercalates into the cavities of themontmorillonite. To the suspension, sulfochlorinated polysulfonedissolved in tetrahydrofuran is then added. The sulfochloride content ofthe thermoplastic is approximately 0.5 groups per repeating unit. Thesuspension is stirred, gently degassed and knife-coated into a film on aglass plate. The tetrahydrofuran is evaporated at room temperature. Thecontent of montmorillonite is chosen to be between 5 and 10 weight % ofthe added sulfochlorinated polysulfone. Once the film is totally dried,the film is peeled off in deionised water and cured in 10% hydrochloricacid at 90° C. Hereby, the sulfochloride groups are hydrolyzed andreacted to sulfonic acid groups. The resulting membrane is additionallycured in water of 80-90° C., until hydrochloric acid is no longerdetectable.

[0065] A sulfochlorinated polysulfone having 0.5 SO₂Cl groups perrepeating unit corresponds, after hydrolysis, to a cation exchangecapacity of 1.0 milliequivalent per gram. Due to the additional sulfonicacid groups from the aminoarylsulfochloride, the cation exchangecapacity increases remarkably, corresponding to the quantity thereof,and is not water-soluble. At the same cation exchange capacity,exclusively sulfonated polysulfone is water-soluble.

[0066] 2) Sulfonated polyetheretherketone, having a cation exchangecapacity (IEC) of 0.9 milliequivalent per gram, is dissolved in hot(T>80° C.) N-methylpyrrolidone (NMP). The sulfochlorinated form havingsuch a content is not soluble in THF. Polymeric sulfonic acids and theirsalts are not, or only to a very small extent, soluble in THF. To thissolution, a suspension of montmorillonite K10, loaded with anaminosulfonic acid, in NMP is then added. Herein, the sulfonic acidgroups are present on the surface, whereas the amino groups are in thecavities of the montmorillonite. The composition of the suspension isagain chosen for a solid content to be between 2 and 20 weight of thepolymer content. It depends on the application for which the membrane isused. The suspension is processed to a membrane, as above. The solventis evaporated in a drying board at a temperature between 80° C. and 150°C. The membrane is peeled off from the glass plate and cured indeionized water for 12 hours at 90° C.

[0067] 3) Sulfochlorinated polysulfone and aminated polysulfone aredissolved in THF. Then, 10 weight % of montmorillonite K10 (dried and inprotonated form) is added. The suspension is stirred, degassed andprocessed to a membrane, as above. The membrane is peeled off from theglass plate and then cured in diluted HCl at 80° C., whereby thesulfochloride group is rehydrolyzed to the sulfonic acid. Then, themembrane is again further treated with deionized water, until all thehydrochloric acid is removed from the membrane.

[0068] It has now been found that the composites relating to theinvention have surprising properties:

[0069] The composites have excellent ionic conductivities even attemperatures far beyond 100° C. Especially, the proton conductivities ofthe composites are still excellent in this temperature range, due to, onone hand, the water storing properties of the clay materials and, on theother hand, the self-proton conducting properties of the clay materials.The good proton conductivities permit the use of these composites inmembrane fuel cells in the above mentioned temperature range.

[0070] Due to the silicates forming cavities, the chemical, mechanical,and thermal stability of composite membranes is significantly increased,because the polymer molecules and the clay minerals and zeolites,respectively, can interact with each other in the cavities. Especially,ionomer blends containing basic polymers and base polymer components mayintercalate into the Lewis acid cavities of the silicates, due to theinteraction of the base groups, whereby an ionic cross-linking betweenthe acidic silicate and the basic polymer chain is formed, which,depending on the system, may be pH independent, contributing to anincrease in mechanical, chemical, and thermal stability, in particularif the composite membranes are used in a strongly acidic or alkalinemedium.

[0071] Used in DMFC, the composite membranes relating to the inventionshow a reduced methanol permeability and gas-through-diffusion acrossthe membrane. Therein, the methanol permeability and the permselectivityof the membrane can be fine tuned at will by:

[0072] The kind of phyllosilicate/tectosilicate

[0073] The mass percentage of the silicate in the composite

[0074] Targeted incorporation of spacer molecules and bifunctionalmolecules into the silicate cavities. The kind and strength of theinteraction of the spacer molecules with the permeate molecules herebydepends on the kind of their functional groups facing outwards and thekind of the functional groups of the permeate molecules. For example, anaminosulfonic acid or an amino carboxylic acid is coupled with the aminefunctionality in exchange of alkali-bentonite on the bentonite surface.The second functional group is available for the reaction with polymersor for proton transport in electromembrane processes.

[0075] The membranes according to the invention show a stronglydecreased fouling (microbial attack of the ionomer membranes by fungiand bacteria), in comparison to conventional ionomer membranes, and thisalready at a content of 2-5% of silicate (montmorillonite) in theionomer membrane. This property is due to the clay minerals blended withthe composite. It has been known for long that clay minerals may act assoil improving agent by strongly slowing down the microbial degradation,especially by fungi. It is surprising that this property of clayminerals is also shown in membranes which contain clay minerals. Due tothis property of the composites according to the invention, their use inmembrane separation processes in water and waste water applications ispossible and also in any other oxidizing environment, containing, e.g.,hydroxy radicals and/or hydrogen peroxide.

[0076] The catalytic properties of the silicate Lewis acids, from whichthe clay minerals according to the invention are made, can also be usedin the composites according to the invention.

EXAMPLES

[0077] 1. Sulfonated polyetheretherketone (sulfonation degree 70%) isdissolved with 5 weight % of montmorillonite in DMAc and knife-coated toa membrane of 50 μm thickness after evaporation of the solvent. Thismembrane is put into an aqueous medium contaminated with fungi. Noattack by fungi is identified. The blank without montmorillonite isheavily colonized and attacked.

[0078] 2. a) Sulfonated polysulfone in salt form and polyvinylpyridineis blended in such a ratio that the final capacity is 1 milli equivalent[H⁺] per gram of the total blend. Both polymers are dissolved in DMAcand processed to a membrane. The specific resistance of this membrane is33 ohm·cm.

[0079] b) To an identical blend as in 2a, additionally 8 weight % ofactivated montmorillonite is added, and the blend obtained is processedto a membrane as in 2a. The specific resistance is 27.7 ohm·cm.

[0080] 3. Polybenzimidazole dissolved in DMAc is mixed with 10 weight %of activated montmorillonite and as a blank without the phyllosilicate.Either blend is processed to a membrane, and the resistances aremeasured by impedance spectroscopy. Without the phyllosilicate, theresistance is 588 ohm·cm, with the phyllosilicate, 276 ohm·cm.

We claim:
 1. An ion conducting composite comprising: (A) a polymer; (B)an acid-base component comprising an acid, a base, or both; and (C) aphyllosilicate, tectosilicate, or both, wherein components (A) and (B)are combined into the polymer thereby providing an acidic and/or basicgroup on the polymer, wherein the sum of the amounts of the acid-basecomponent and the polymer are from 1 to 99 weight % and the amount ofphyllosilicate and/or tectosilicate is from 99 to 1 weight %, andwherein an acid and/or a base is present in the cavities of thephyllosilicate and/or tectosilicate.
 2. The composite of claim 1,wherein an ionomer provides both components (A) and (B), wherein theionomer is selected from the group consisting of: (a) a cation exchangepolymer comprising a cation exchange group —SO₃H, —COOH, and/or —PO₃H₂,wherein the polymer can be non-cross-linked or covalently crosslinkedand the polymer backbone can be a vinyl polymer, an aryl main chainpolymer, polythiazole, polypyrazole, polypyrrole, polyaniline,polythiophene or any blend of these; (b) an anion exchange polymercomprising an anion exchange group —NR₃ ⁺, PyrH⁺, ImR⁺, PyrazR⁺, TriR⁺,and/or other organic basic aromatic and/or non-aromatic groups, whereinR is a hydrogen, alkyl, or aryl group, wherein the polymer isnon-cross-linked or covalently crosslinked, and wherein the polymercomprises a vinyl polymer, an aryl main chain polymer, polythiazole,polypyrazole, polypyrrole, polyaniline, polythiophene, or a blendthereof, (c) a polymer containing on the polymer chain both anionexchange groups from (b) and cation exchange groups from (a), whereinthe polymer comprises a vinyl polymer, an aryl main chain polymer,polythiazole, polypyrazole, polypyrrole, polyaniline, polythiophene, ora blend thereof; or (d) a blend of (a) and (b), wherein the mixing ratiocan range from 100% of (a) to 100 % of (b), wherein the blend iscovalently and ionically cross-linked, and wherein the polymer comprisesa vinyl polymer, an aryl main chain polymer, polythiazole, polypyrazole,polypyrrole, polyaniline, polythiophene, or a blend thereof.
 3. Thecomposite of claim 1, wherein a precursor of an ionomer provides bothcomponents (A) and (B), wherein the precursor is selected from the groupconsisting of: (a) the precursor of: a cation exchange polymer (a1)comprising COHal, CONR₂, or COOR groups; a cation exchange polymer (a2)comprising SO₂Hal, SO₂NR₂, or SO₂OR groups; or a cation exchange polymer(a3) comprising PO₃Hal₂, PO₃(NR₂)₂, or PO₃(OR)₂ groups, wherein R is ahydrogen, alkyl, or aryl group, and wherein Hal is a fluorine, chlorine,bromine, or iodine atom; or (b) the precursor of an anion exchangepolymer comprising —NR₂, pyridyl, imidazolyl, pyrazolyl, triazolyl,and/or other organic basic aromatic and/or non-aromatic groups, whereinR is a hydrogen, alkyl, or aryl group, and wherein Hal is a fluorine,chlorine, bromine, or iodine atom.
 4. The composite of claim 1, whereinthe phyllosilicate is a bentonite.
 5. The composite of claim 4, whereinthe bentonite is montmorillonite.
 6. The composite of claim 1, whereinthe phyllosilicate is a pillared phyllosilicate.
 7. The composite ofclaim 1, wherein the tectosilicate is a zeolite.
 8. The composite ofclaim 1, wherein the zeolite is clinoptilolite.
 9. The composite ofclaim 2, characterized in that the basic component contains imidazole,vinylimidazole, pyrrazole, oxazole, carbazole, indole, isoindole,dihydrooxazole, isooxazole, thiazole, benzothiazole, isothiazole,benzoimidazole, imidazolidine, indazole, 4, 5-dihydropyrazole,1,2,3-oxadiazole, furazane, 1,2,3-thiadiazole, 1,2,4-thiadiazole,1,2,3-benzotriazole, 1,2,4-triazole, tetrazole, pyrrole, aniline,pyrrolidine, or pyrrazole groups.
 10. The composite of claim 2, whereinthe ionomer is an ionomer blend (d), and wherein the phyllosilicate ismontmorillonite.
 11. The composite of claim 2, wherein the ionomer is anionomer blend (d), and wherein the phyllosilicate is clinoptilolite. 12.The composite of claim 3, wherein the polymer component (A) comprises anacid polymer, and wherein the backbone of the polymer comprises one ormore of the following repeat units: R_(aromatic) R_(bridge)


13. The composite of claim 1, wherein the polymer component (A) is abasic polymer, and wherein the backbone of the polymer comprises one ormore of the repeat units of claim 12 or comprises one or more of thefollowing repeat units:


14. The composite of claim 1, wherein components (A) and (B) arecombined into 1) a polymer comprising an acidic group and 2) a polymercomprising a basic group, and wherein both polymers are incorporatedinto the composite.
 15. The composite of claim 1, wherein the compositemaintains ion conduction over the temperature range of from −40° C. to200° C.
 16. The composite of claim 15 adapted to be a component of afuel cell.
 17. The composite of claim 1 adapted to be a reverse osmosisor (electro)membrane, wherein the membrane is capable of separating twoor more gases or liquids.
 18. The composite of claim 1 adapted to be acatalytic membrane or a component of a membrane reactor.
 19. Thecomposite according to claim 1, further exhibiting thermal resistance upto 400° C.
 20. A process for the preparation of the composite of claim1, comprising the step of contacting the polymer component, theacid-base component, and the phyllosilicate and/or tectosilicatecomponent, optionally with a solvent, at a temperature from −40° C. to300° C.